[Effects of beta-carotene on genotoxic lesions in the liver under formation and action of carcinogenic N-nitrosodimethylamine].

beta-carotene pretreatment of rats decreased the methylation and formation of single-strand breaks in DNA and also decreased activity of alanine-aminotransferase, sorbitol dehydrogenase, gamma-glutamyl transpeptidase activities, caused by action of N-nitrosodimethylamine or synthesis of this carcinogen from precursors.